Since he clinched the Democratic nomination last month, Barack Obama has consistently led John McCain in the polls. But his lead has been generally modest. He never received a bounce from becoming the nominee, and today his lead is almost paper-thin - generally about four points in most polls.

The electoral environment is still tilted heavily toward Democrats. In generic congressional ballot polls, Democrats maintain a steady double-digit lead over Republicans. Which means that Obama is running behind the Democratic Party in general.

The other important metric is the right-track/wrong-track poll number, where respondents are asked if they believe the country is generally moving in the right, or wrong, direction. Today, only 15 percent say right track; 78 percent say wrong track.

Since Obama began his ascendancy in January, the wrong-track numbers have actually increased. But strangely, Obama, whose entire campaign has been centered on the promise of "change," hasn't been helped by this increasingly pessimistic view of the future.

Even by the measure of money, Obama is underperforming. Perhaps it's unfair to hold him to the amazing standard he set this winter, but before recording a $52-million June, his fund-raising numbers had declined for three straight months.

Clearly, something is going on. Three possibilities come to mind:

First, people forget that Obama won the nomination by gaming the system, not getting the most votes.

This isn't meant to diminish his accomplishment. Obama won fair and square, and his insurgent victory against a heavy favorite was the most impressive upset since Jimmy Carter captured the nomination in 1976. Obama earned the nomination. But it does mean that Obama's electoral base may not be as broad or deep as you might assume.

Second, Obama made a strategic decision to abandon his original, central campaign narrative in favor of repositioning himself closer to the political center.

For the last year, the pitch was that this freshman senator was not a typical politician. He promised to eschew politics-as-usual and be a different, more principled, kind of leader. During the last eight weeks, though, Obama has abandoned a host of earlier, left-ish positions - on FISA, public financing, Iraq and more - in order to position himself closer to the center.

On one level this makes sense; America has never elected a president as liberal as the Obama of the Democratic primaries. So Obama is now much closer to the political mainstream and is more ideologically electable. By changing some of his policy positions, Obama closed off certain avenues of attack.

But the price of this move was his original narrative: It is now difficult for Obama to claim to be anything other than an ordinary, hard-nosed politician. Only time will tell if this retrenchment was smart.

But the most important shift in the dynamic of the race is that Obama has become, for all intents and purposes, the incumbent.

Partly, this is the fault of the media, which, with a few exceptions, have crafted an aura of invincibility about Obama. But the candidate has done his part to appear as though his ascension need only be ratified in November.

Obama has talked about his plans to redecorate the Lincoln bedroom and has proposed that he address the German people from the Brandenburg Gate (a position usually reserved for heads of state). He has referred to his time as a senator in the past tense and even gone so far as to craft his own, personalized version of the presidential seal, which he used at an event in Chicago.

All of which has the effect of making the election not about John McCain or President Bush or even the Republican Party, but about Barack Obama. And as a matter of optics, it ties Obama to the status quo. As the presumptive president, he is no longer the outsider or the challenger, but rather the establishment figure to be approved or rejected.

It's an interesting gamble, and Obama may very well pull it off. But why he would trade his standing as an insurgent candidate running against the incumbents for a position as the assumed commander-in-chief is anyone's guess. The inevitable establishment figures haven't done all that well this cycle.

Every weekday JewishWorldReview.com publishes what many in the media and Washington consider "must-reading". Sign up for the daily JWR update. It's free. Just click here.

Jonathan V. Last is a columnist for the Philadelphia Inquirer. Comment by clicking here.

Previously:

06/26/08 Bush failed to hold others responsible for their mistakes, and he let his admirable vice president do too much
02/18/08 GOP will unify as Obama and Clinton continue to vie12/13/07 Fun begins as races tighten and shift12/05/07 Iran's future: Would lower fertility rates lead to stability?11/01/07 Nobel Prize in Economics  where Team USA still dominates the game10/25/07 Handicapping the GOP's presidential horse race10/11/07 Germany's Turks provide a lesson on immigration09/13/07 British battle can offer us a perspective on casualties09/12/07 Alas, GOP seems set to take hit in Senate08/30/07 Europeans have supplanted backbones with capitulation08/24/07 Politics holds the key to ensuring a healthy growth in population08/17/07 Finessing the Democratic center08/10/07 Woohoo! Satire seeing a revival07/31/07 Historical model: For Obama, it's Carter07/26/07 Baseball, apple pie, a 2nd chance07/24/07 Harry Potter and the alchemy theory07/06/07 Life is hard  and often short. The perils of professional wrestling06/21/07 After Bush: Gingrich and others worry that his shortcomings could have a far-reaching effect on the GOP03/09/07 Why the British outclass us in acting01/23/07 Romney: Seriously great, but with baggage12/23/06 When truth is transpicuous12/05/06 A realistic plan: Split the country in two11/08/06 We could easily pull out of Korea and let China have regional hegemony. But would it be the right thing?10/24/06 The decline of revolution10/18/06 Why the free market is king08/07/06 Democracy, of itself, not solution to all problems08/01/06 We get the movies we deserve07/27/06 How long will U.S. empire last?